Drive-chain.



1. 1. BYUCHER.

DRIVE CHAIN. I APPLICATION HLED JUNE 22 1915.

1,21 8,368. Patented Mar. 6, 1917.

. msntrnn STATES PATENT- orrion.

.JoHAmT Josnrrr nucnnn, or ZURIGH-ENGE, SWITZERLAND.

DRIVE-CHAIN.

To all whom it may concern:

Be 'it known that I, JoHANN JOSEPH BUCHER, citizen of Switzerland, residing at Zurioh-Enge, Switzerland, have invented 5 certain new' and .useful Improvements in Drive-Chains, of which the following isa "specification, reference being had therein to the accompanying drawing.

One of the objects of the present invention is to provide a drive-chain which is especially adapted for nearly noiseless transmission of considerable or small energy such as occuring for instance in motorcycle-drives and the like in such a manner 15. that any wear and' tear is eliminated.

A further object is to manufacture the links of said drive-chain in a particular manner allowing their easy connection to form the chain and dispensing with the use of rivets, pins, screws, nuts'and likensual auxiliary elements. I

A still furtherobject of my present invention is to reduce or nearly avoid v the loss of energy as it is caused in the working of usual chain-drives by the pivots forced into the spaces between the teeth of the sprockets.

Another feature of my invention consists .in means for preventing any dangerous lateral movement of the chain such as is usual in most chain-gearing.

Referring to .the drawing showing one form of construction of my improved cha.1n-' gear,

Figure 1 is a lateral view of the chaindrive; i Fig. 2 a front view thereof, and

Fig. 3 a perspective view of the chainelements.

As it is evident from the Figs. 1 and 2, w is a sprocket which is distinguished in its construction by its rims a being of a certain width on both sides of the toothed middle portion a of the sprocket.

The links or braces b forming together with the pivots c all the integral elements of the drive-chain are preferably made from weldless steel-tube'drawn-to double U-profile and cut -to'short pieces. f

'It is well understood that any other method can likewise be followed for the manufacture of these fiat and open links 6, as for instance a method comprising a special machine making those links of bandsteel fed to it. Y

In thismachine the said material is cut Speciflcation of Letters Patent.

, 6. These pivots 0 may also form, of course,

the object of an automatic manufacture.

Patented Mar. 6, 1917.

Application filed June 22, 1915. Serial No. 35,719. i

= From Fig.' 3, as well as from the others,

' it is evident that the improved drive-chain is formed b mere junction of the described pivots and inks, the latter being preferably made, .as stated, of thin material.

Hereby suflicient elasticity or resiliency is imparted to the links b, so that they can- .besomewhat opened or widened in their middle portion and consequently passed over the heads formed at the ends of the pivots c.

From the foregoin it will be seen, that y no auxiliary parts 0 any kind have to be prepared for assembling the elements of the chain.

In the case when the links 6, in order to render the same capable of transmitting considerable power, are made from steel of greater thickness, the elasticity of these links is necessarily more or less reduced.

In this-case the links 6 must of course be somewhat wider or opened in their middle portion, to that effect a spreader being used or the links being originally madeof the desired profile.

After these links are engaged upon the pivots c, the former arefiattened with the aid of a special pressing device, whereby a perfectly well assembled drive-chain is likewise formed as in the case of junction of thin elastic links.

As to the operation of the drive-chaincomposed according to the foregoing exlanation, it is evident also from the drawings' that it is essentially distinguished byv sprocket-teeth.

Such regulationis very important, because in Galls chains, to which group of chains my drive chain belongs the pivots are always mitted and necessarily produces an accelerated or premature wear of the parts working together.

All dimensions of the elements of my chain being in mutual accordance, it is evi dent that the pivots c are not forced too deep into the spaces provided between the teeth of the sprocket wheel, as the inner sides of the links I) run on the rims.

Owing to the quite open formation of the links 7) the drive chain is simultaneously rendered more or less elastic according to the thickness of the material of which the said links are made.

If the new chain is employed for normal or light duty, the links 6 can of course be made of very thin steel, so that they have sufficient resiliencyto bend during their .passage around the rims a For heavy duty the links I) of my new chain, being made of thicker material, necessarily offer greater rigidity, so that, by virtue only of their open form,' they assume but a slight curvature during their running upon the rims a These working conditions are quite those which are required from the kinematic point of view and rigorous with regard to the power that is to be transmitted in each case, such transmission being always effected with the least possible loss of energy.

At the same time the known slapping noise of a chain-gear is avoided on the said favorable conditions of running of my improved chain, and such noiseless function gives evidence also of a perfect continuity of run.

By virtue 'of all these new and important working qualities the effect of my improved drive-chain can be compared to a high extent to that of driving belts or cords which are distinguished by their soft and easy running.

Indeed, especially for the power-transmission as-it occurs for instance in motorcycles, engineers hitherto mostly recurred to the use-of leather belts or cords,- though these need strong tension and always increase in length.

These drawbacks are entirely eliminated vention is used. At the same time a considerable increase of the working speed may be attained without affecting the noiseless running of the chain in any degree.

In the foregoing my improved drive-chain being essentially described in accordance with the drawing, it is yet to be stated, that instead of the shown single pairs of links Z) engaging the neck portions of the pivots, there. may be provided more than two links engaging the neck portions, so that it can also be used for the transmission of a greater power. Thus for heavy duty it is possible to employ my chain either of such augmented width or with thicker links.

I The use of the first of these two kinds of chain is recommendable especially when the speed of rotation to be transmitted is great, as the greater number of 'links permits them to be made very thin.

On the contrary the other kind of chain ,with thicker links I) will be employed in the case when.the speed of rotation to be transmitted is not considerable and when it is desired to avoid greater width of the chain.

I claim as my invention:

1. A drive chain consisting of a plurality of connected resilient elongated loops of flat spring metal, each loop adapted to conform automatically to the curvature of the wheels during contact therewith.

2. A drive chain consisting of a plurality of resilient elongated loops of fiat spring metal having semi-cylindrical ends, each loop adapted to conform automatically to the curvature of the wheels during contact therewith, and connecting pivots provided near each of their ends with an annular neck portion to receive said semi-cylindrical ends of the loops arranged side by side.

3. A chain drive comprising a sprocket wheel having a toothed middle portion and an annular rim portion on each side thereof, resilient elongated loops, and connecting pivots each provided near its two ends with neck portions of reduced diameter adapted to receive the semi-cylindrical ends of two of said loops arranged side by side, flattened portions of said loops acting in a resilient manner on said rim portions.

Signed at ZurichfEnge, in the State of Switzerland, this 7 1; day of May, A. D. 1915. J OHANN JOSEPH BUOHER.

\Vitnesses:

BERTHA C. GRoB, CARL GUBLER. 

